In the manufacture of glassware by the conventional process using a conventional individual section glassware forming machine, a gob of molten glass is first formed into a parison either by pressing or blowing in a blank or parison-forming mould at a blank station of the machine. The parison is formed in an inverted position at the blank station, and is transferred directly to a shaping station where the parison is presented in an upright position ready for final shaping of the article of glassware by the application of air under pressure inside the parison in a blow mould at the shaping station. The parison is thus inverted through 180.degree. during transfer from the blank station to the shaping station.
During this transfer the parison is held by its finish in the neck rings of a pneumatically driven inverting mechanism and, as the parison is moved through 180.degree., the parison passes through a range of positions in which the gravitational and centrifugal forces are acting to bend the parison about its finish. There is, therefore, a serious risk of damage to the finish as well as to the parison itself, and it is important to control the movement of the inverting mechanism in such a way as to minimise the deformation forces which are acting upon the parison and its finish during the inverting movement.
Damage to the parison and its finish can also arise from the impact forces generated when the arm of the inverting mechanism which carries the neck rings is brought to rest at the end of the stroke of the pneumatic piston and cylinder device which the drives the inverting mechanism. These impact forces act on the parison and its finish when the parison is in a vertical position, thereby presenting a different problem of damage which is additional to that which arises during the inverting movement.
Exactly similar problems arise in a three station individual section machine in which the parison is formed in an inverted position at the blank station and is transferred with an inverted movement from the blank station to an intermediate station where the parison is presented in an upright position for reheating before subsequent transfer of the parison from the intermediate station to a shaping station, which is the third station of the machine.